Phenotypic changes in transgenic tobacco plants caused by expression of the antisense form for the hmg1 gene

Tobacco plants were genetically transformed with the Arabidopsis thaliana h eterologous hmg1 gene encoding 3-hydroxy-3-methylglutaryl-CoA reductase, a key enzyme involved in the metabolism of terpenoid compounds. The hmg1 gene was inserted under the control of the 35S RNA double promoter from the cau liflower mosaic virus (CaMV 35S) in both direct and reverse orientations re lative to the promoter. DNA analysis by polymerase chain reaction (PCR) and Southern blotting confirmed the transgenic nature of the tobacco plants ob tained. DNA-RNA hybridization revealed expression of the hmg1 gene in these tobacco plants. The plants transformed with the antisense copy of the hmg1 gene differed from the control plants in delayed development and in flower color and shape.